• An aerial view of Old Faithful erupting taken from Observation Point with the Old Faithful Inn to the side.

    Yellowstone

    National Park ID,MT,WY

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  • Construction Work To Result In Yellowstone Road Closures After Labor Day

    Two sections of Yellowstone’s Grand Loop Road will be closed due to construction after the Labor Day holiday weekend. Travel between some points will involve long detours and significantly longer than normal travel times. More »

Hot Springs and How They Work

Emerald Spring glows green.

Emerald Spring

Hot springs with names like Morning Glory, Grand Prismatic, Abyss, Emerald, and Sapphire, glisten like jewels in a host of colors across the park's harsh volcanic plain. They are the most common hydrothermal features in the park.

Their plumbing has no constrictions. Superheated water cools as it reaches the surface, sinks, and is replaced by hotter water from below. This circulation, called convection, prevents water from reaching the temperature needed to set off an eruption. [View the anatomy of a hot spring.]

Did You Know?

Seventh Cavalry Ensignia Pin.

Prior to the establishment of the National Park Service, the U.S. Army protected Yellowstone between 1886 and 1918. Fort Yellowstone was established at Mammoth Hot Springs for that purpose.